The maximum punishment for causing death by a negligent act is a two-year jail term with fine.

Officers from the Ministry of Manpower's (MOM) Occupational Safety and Health Inspectorate were also alerted and went to the scene immediately to investigate.

The LTA said it was deeply saddened at the fatal accident and will work with Gammon as well as main contractor Jurong Primewide to help the families of the affected workers.

The LTA said it would assist MOM and police with investigations.

Gammon could not be reached for comment.

There have been 55 workplace deaths so far this year, with 20 deaths in the construction sector.In May, Mr Riyade Hussain, a 23-year-old worker, died at the Mandai Depot construction site after he was pinned under a metal truss that had fallen from a trailer. He had come to work here from Bangladesh just five months earlier.